Meeting Abstract
Disturbance in patches of Northern hardwood forests by periodic burns can lead to sequences of succession in which microbial and soil/litter dwelling invertebrate communities may vary in response to changes in tree and plant communities. The presence of many invertebrates, in particular detritivores, can drastically alter leaf decomposition as they make leaf material more readily available to microbes, which may result in varying decomposition rates depending on the stage of succession. This is significant as heterotrophic respiration during decomposition is a major input of carbon dioxide into the atmosphere, and the effects of invertebrates are often overlooked. Our study took place in Northern Michigan, along an experimental burn chronosequence consisting of 6 plots ranging in age from 20 to 100 years old. To examine the differences in decomposition along this successional gradient, we set out 3 treatments of litter bags in each plot, with each of the treatments being a composite mixture of leaves from either the oldest growth forest, mid-growth forest, or earliest growth forest. Two sets of replicates, one with a fine mesh and one with a course mesh, were created to illuminate the effects of invertebrate presence vs. invertebrate absence. We find that due to variation in plant and invertebrate communities, along with varying micro-climates, rates of litter decomposition vary across the sequence, with older plots showing accelerated rates of decomposition. The invertebrate-present replicates displayed accelerated rates of decomposition as expected. We also find that the litter mixtures most similar to their plot of origin decompose more efficiently, potentially due to home-field advantage effects of the microbial communities.
